The size and distance between device structures is decreasing as the device concentration on integrated circuits continues to increase. However, the vertical heights of the gaps or trenches during manufacturing in the device normally do not decrease as fast as their horizontal widths. As a result, the gap or trench structures have larger ratios of height to width (i.e., higher aspect ratios).
While the ability to make device structures with increasing aspect ratios allows more of the structures (e.g., transistors, capacitors, diodes, etc.) to be packed onto the same surface area of a substrate, it has also created fabrication problems. One of these problems is the difficulty of filling deep narrow gaps or trenches without creating a void or seam in the material that fills the gaps or trenches. As the gaps or trenches during manufacturing decrease in size, and depositing material into the gaps or trenches becomes increasingly difficult, and increasingly likely to form a void.